Hi sir:
The first thing to do is:
1) test the power supply in CU unit of Polar
a)+5vdc b) +24Vdc c)+42Vdc
2) Please see if there are in tolerance about. 0.7% up or down.
3) Do before to measure power supply, clean it the edge connector very well for dirty, corrosion, etc.
Let me know. sincerely
Blessing